The field of the disclosure relates generally to component surface temperature measurement, and more specifically, to methods and a system for measuring component surface temperature in harsh environments based on hyperspectral imaging.
At least some known turbomachines, such as gas turbine engines, include a plurality of rotating turbine blades or buckets that channel high-temperature fluids, i.e., combustion gases, through the gas turbine engines. Known turbine buckets are typically coupled to a wheel portion of a rotor within the gas turbine engine and cooperate with the rotor to form a turbine section. The turbine buckets are typically spaced circumferentially in a row extending about the rotor. Moreover, known turbine buckets are arranged in axially-spaced rows that are separated by a plurality of stationary nozzle segments that channel the fluid flowing through the engine towards each subsequent row of rotating buckets. Each row of nozzle segments, in conjunction with an associated row of turbine buckets, is usually referred to as a turbine stage and most known turbine engines include a plurality of turbine stages. The arrangement of turbine buckets and nozzle segments is referred to as a hot gas path.
Such known turbine buckets and nozzle segments in the hot gas path may wear over time. For example, such components may exhibit stress-related cracking induced by temperatures at or above predetermined parameters. Furthermore, coatings are applied to such components to protect the components from temperatures of the hot gas path. Therefore, many known gas turbine engines include temperature monitoring systems that provide operational temperature data in real time, i.e., at the time of measurement. At least some of these known temperature monitoring systems monitor and record temperature data as an input to adjust operation, e.g., the firing rate of the gas turbine engine, i.e., the rate or ratio of fuel and air being combusted in the engine. In some cases, the temperature data may be used as an input into certain protective features of the engine.
A key challenge in the conversion from intensities to surface temperatures in gas turbine measurements is to separate the contributions from different sources in each point. Generally, the balance will vary over both time and over a given surface due to, for example, fouling and wear of surface and optics, and run conditions. Another key challenge is the measurement of the gas temperature in front of the blade/bucket. Another challenge in collecting thermal data from the surface of components of an asset while the asset is operating at high-temperatures is due to nature of the environment that the components are operating in. Impurities, such as soot and hot vapors, may also interfere with readings.